Goodman Forced Air Furnace does not turn on

[efg20]

I have a goodman forced air furnace (model gmph075-4). When I turn on the heat on the thermostat the furnace does not turn on at all.

The fan, however, works fine.

Do I need to replace a fuse? Any ideas would be greatly appreciated.

[SeattlePioneer]

Is "the fan" air one that circulates air through the house or the small motor that turns on when the thermostat calls for heat?

[efg20]

The one that circulates air through the house.

[ecman51`]

That other fan has to come on before anything else occurs. It could be the fan motor is seized up, or not getting power. There is a relay involved that takes 24 volt ac thermostat power and clicks on to complete a 120 volt circuit to that ventor(inducer) fan.

Also IF you have a 3-wire(as opposed to 2-wire) pressure switch...if the vacuum diaphram plunger is stuck over the wrong way, it will not allow the ventor to start up. And thast can be caused by not just a faulty pressure switch: I have seen water in the condensate line hold back that plunger, and not let the ventor and furnace start up! Blow out your condensate drain hose lines, bothj toward the drain and also up toward into the furnace.!